The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 0ecc5be200c84e67114f3640064ba2bae3ba2f5a
Gitweb: https://git.kernel.org/tip/0ecc5be200c84e67114f3640064ba2bae3ba2f5a
Author: Yuntao Wang <yuntao.wang@xxxxxxxxx>
AuthorDate: Tue, 13 Aug 2024 09:48:27 +08:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 13 Aug 2024 15:15:19 +02:00
x86/apic: Make x2apic_disable() work correctly
x2apic_disable() clears x2apic_state and x2apic_mode unconditionally, even
when the state is X2APIC_ON_LOCKED, which prevents the kernel to disable
it thereby creating inconsistent state.
Due to the early state check for X2APIC_ON, the code path which warns about
a locked X2APIC cannot be reached.
Test for state < X2APIC_ON instead and move the clearing of the state and
mode variables to the place which actually disables X2APIC.
[ tglx: Massaged change log. Added Fixes tag. Moved clearing so it's at the
right place for back ports ]
Fixes: a57e456a7b28 ("x86/apic: Fix fallout from x2apic cleanup")
Signed-off-by: Yuntao Wang <yuntao.wang@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/all/20240813014827.895381-1-yuntao.wang@xxxxxxxxx
---
arch/x86/kernel/apic/apic.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 66fd4b2..3736386 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1775,12 +1775,9 @@ static __init void apic_set_fixmap(bool read_apic);
static __init void x2apic_disable(void)
{
- u32 x2apic_id, state = x2apic_state;
+ u32 x2apic_id;
- x2apic_mode = 0;
- x2apic_state = X2APIC_DISABLED;
-
- if (state != X2APIC_ON)
+ if (x2apic_state < X2APIC_ON)
return;
x2apic_id = read_apic_id();
@@ -1793,6 +1790,10 @@ static __init void x2apic_disable(void)
}
__x2apic_disable();
+
+ x2apic_mode = 0;
+ x2apic_state = X2APIC_DISABLED;
+
/*
* Don't reread the APIC ID as it was already done from
* check_x2apic() and the APIC driver still is a x2APIC variant,
|